Composite decking is a decking material that combines wood with plastic or cellulose fibres to make the wood stronger and resistant to weathering. The most effective type of composite decking uses a wood preservative along with the cellulose additives. Gluing composite decking is one way to hold the decking in place, although it is meant as a supplemental attachment method along with nails or screws. The benefit of using glue is that it creates a strong bond between the decking and other surfaces, making it much harder for the deck to rot because exposed areas of the wood remain sealed.
Clean the area where you want to install the decking with a pressure washer. Wear safety goggles when working with a pressure washer to protect your eyes from the high pressure of the water spray. This will remove all dirt and contaminants and create a stronger bond between the under surface and the decking. Allow the area to dry for at least four hours.
Apply a line of glue to the bottom of each deck piece and along the edges as well. Press the decking firmly into the surface. Quickly glue another deck piece and lay it beside the first one, making sure the sides of the deck pieces rest against each other.
Screw or nail the decking into place. Use one nail per corner of the deck piece, then one additional nail every 1 to 2 feet apart on both sides.
Use a vice grip or other heavy weight to hold decking in place where it cannot be screwed, or when repairs are necessary, such as when a piece of decking comes loose from the surface. This will hold the decking down firmly, creating a bond that is difficult to break.
Make sure to use construction-grade, waterproof adhesive. This is the only kind of adhesive strong and tough enough to hold the deck pieces in place. The waterproof glue will also hold up against rain and other water. A waterproof glue will actually help extend the life of the decking because it is much harder for water to seep through a glued seal than it is for water to seep into exposed decking.
Do not glue the composite decking in place if it will void the warranty. Some manufacturers do not want glue used with their products. Check the warranty paperwork or installation instructions for the decking before using glue to hold the deck in place.